Presence of a metabotropic and an ionotropic purinergic receptor on
rat submandibular ductal cells.
Amsallem, Hagai, Mourad M[umlaut]atioui, Astrid Vandenabeele,
Abdelmoutalib Elyamani, Arie Moran, and Jean-Paul Dehaye.
Department of Physiology, Corob Center for Medical Research,
Faculty for Health Science, Ben-Gurion University, Beer-Sheva, Isral;
Laboratoire de Biochimie g[umlaut]an[umlaut]arale et humaine,
Institut de Pharmacie, Universit[umlaut]a libre de Bruxelles, B-1050
Brussels, Belgium; 3, Laboratoire de Stomatologie, Facult[umlaut]a de
M[umlaut]adecine, Universit[umlaut]a libre de Bruxelles, Route de
Lennik, B-1070 Brussels, Belgium
APStracts 3:0184C, 1996.
ATP (1 M -1 mM) increased the [Ca2+]i in rat submandibular ductal
cells. The dose-response curve was biphasic with a first plateau
around 10 M and a second increase at concentrations higher than 100
M. This second increase was abolished in the absence of extracellular
calcium or in the presence of Coomassie blue and could be mimicked by
benzoyl-ATP. The activation of this response increased the uptake of
extracellular manganese and the release of kallikrein, a ductal cell
marker. The response at low concentrations of ATP was mimicked by
ADP, 2-methylthioATP (which was the most potent agonist), ADP S and
UTP. Removal of extracellular calcium did not abolish this response,
but ADP or 2-methylthioATP had no effect after a preincubation with
thapsigargin. A preincubation with 2-methylthioATP desensitized the
receptor involved in the response to both ADP and UTP. Similarly, a
pretreatment with UTP prevented a further response to ADP. ADP
increased the intracellular concentration of IP3 but did not affect
the secretion of kallikrein. In conclusion, rat submandibular ductal
cells possess two types of purinergic receptors. A metabotropic
(P2Y1) receptor and a P2X-ionotropic purinergic receptor coupled to a
manganese-permeant calcium channel and to kallikrein secretion.
Received 6 December 1995; accepted in final form 24 May 1996.
APS Manuscript Number C731-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 17 June 96